The Obama administration confirmed late Sunday it had delayed the imposition of new ballistic missile sanctions on Iran to ensure the Islamic Republic released five imprisoned Americans under a secret agreement reached on the sidelines of the nuclear negotiations, according to senior administration officials.

The officials confirmed that “secret” talks between U.S. and Iranian officials had been taking place for the past 14 months.

In exchange for the release of the five Americans—including a Washington Post reporter and Christian pastor—the Obama administration pardoned or dropped charges on 21 Iranians convicted of violating U.S. sanctions, including seven who had been detained in the United States, according to a State Department official who spoke to the Washington Free Beacon on background.

Iran, however, said that the number of those “privileged by the deal” stands at 28, though it did not provide evidence to back this claim.